Floating roof tank seal means

ABSTRACT

A seal for a floating roof tank comprising a multiplicity of independent shoes arranged circumferentially about the tank shell and supported and biased against the shell by spring straps secured to the roof and extending therefrom radially outwardly and upwardly and downwardly therefrom and pivotally secured to the upper portions of the shoes. Flexible seal curtain means traverse the space between the upper portions of the shoes and the roof. The shoes, preferably, embody resilient, relatively thin pads in flexible envelopes which bear against the tank shell to accommodate irregularities therein.

United States Patent 2,737,310 3/1956 2,803,371 8/1957Edens..................

William E. Joor, ll Houston, Tex.

\/)) SSS 666 BB 000 222 222 u m M "E m N uunA a J .m .m kgG gcgl. .l iWLWR O 457 666 999 111 ll, 56. 05 34 955 002 333 Q n I 8 in 11 8 d 93$22M 7 e 7OFU 0 6 Ce n Mrm ts D S AFPA 1. .1.1 253 2247 [ill [72]Inventor 224,556 11/1962 Austria......................... 220/26(S)Primary ExaminerDonald F. Norton Assistant Examiner-James R. Garrett[54] FLOATING ROOF TANK SEAL MEANS Attorneys-Bertram H. Mann, Frank B.Pugsley, James G.

3 Claims, 10 Drawing Figs. Ulmer, Delmar L. Sroufe and Robert A. White[52] ABSTRACT: A seal for a floating roof tank comprising a mu]-tiplicity of independent shoes arranged circumferentially about the tankshell and supported and biased against the shell by spring strapssecured to the roof and extending therefrom radially outwardly andupwardly and downwardly therefrom and pivotally secured to the upperportions of the shoes. Flexible seal curtain means traverse the spacebetween the upper portions of the shoes and the roof. The shoes,preferably, embody resilient, relatively thin pads in flexible envelopeswhich bear against the tank shell to accommodate irregularities therein.

B65d 87/18 220/26, 26 (S) 220/265UX 220/26(S)X 220/26(S) 220/26(S)220/26(S) [51] Int. [50] Field [56] References Cited UNITED STATESPATENTS 1,819,401 8/1931 Bailey........................... 1,900,904 3/1933 Berger.. 1,913,643 6/1933 Smith 2,478,422 8/1949 Plummer..

2,576,136 11/1951 Moyer..................

PATENTED FEB23 I97! SHEET 1 OF 5 VV////am i c/oar, I

INVEN'IOR.

ATTOR/Vfy PATENIEDFEB2319I| 3565279 sum 5 [1F 5 ATTORNEY FLOATING ROOFTANK SEAL MEANS FIELD OF THE INVENTION This invention relates to sealsfor floating roof tanks and consists particularly in novel means forlsupporting and outwardly biasing the seal shoes and in constructing theshoes in a more efficient manner than heretofore.

SUMMARY OF THE INVENTION An object of the present invention is toprovide novel efficient and rugged support and biasing means for theseal shoes.

Another object is to provide seal shoe means embodying a multiplicity ofindependent shoes each consisting of rigid backing and a resilientfacing comprising packing of cellular or other resilient materialmaintained in a fluidtight and abrasive-resistant envelope.

In all forms of the present invention, a multiplicity of independentseal shoes are supported and biased against the inner face of the tankshell by spring strap members secured to the periphery of the roof andextending radially outwardly and upwardly and downwardly therefrom andpivotally secured to the upper portions of the shoes. Seal curtainsextend across the annular clearance space between the upper portions ofthe shoes and the top of the roof. In some cases the independent shoesembody relatively thin packings of expanded or other cellular resilientmaterial within an envelope of flexible sheeting for hearing against thetank shell face and for accommodating irregularities therein.

BRIEF DESCRIPTION OF DRAWINGS In the accompanying drawings:

FIG. 1 is a perspective view showing a portion of a floatin roof tankand seal means embodying an exemplary form of the invention, portionsbeing broken away and sectioned.

FIG. 1a is an elevation view showing part of the inside of the tank walland a modified seal.

FIG. 2 is an enlarged detail vertical transverse section takensubstantially on line 2-2 of FIG. 1.

FIG. 3 is a vertical transverse radial section taken on line DESCRIPTIONOF THE PREFERRED EMBODIMENT In FIG. I there is shown a large circulartank shell 12 having a wind girder l3 projecting outwardly adjacent theupper edge thereof. A floating roof including a peripheral pontoonportion 14 and an intermediate pan portion 15 is loosely received withinthe tank for floating on the liquid therein. A support column is shownat 16 to limit approach of the roof to tank floor 17.

Seal shoe structure, generally designated 18, extends entirely aroundthe inner face of shell 12 abreast peripheral wall 19 of the roof. Thisseal shoe consists of an envelope 20 of flexible, abrasive-resistant,fluidtight sheeting, as nylon cloth, impregnated with polyurethane. Theenvelope may be continuous around the tank and encloses cellularresilient material 21 which, likewise, may be continuous. Material 21may be expanded polyurethane foam or the like. Extending along the innerupper edge of the shoe envelope are a plurality of thin but rigid strapbars 23, 24, etc., spaced at their ends, as at 25,

to" permit individual working of the bars. These bars are secured to theupper edge of the resilient shoe material by means of bolts 26, 27, and28. Bridging the end gaps between adjacent bars, as 23 and 24, arespring straps, as 29, of double U configuration, as shown in FIG. 5,with end parts secured to the bars by means of the bolts 26.

Shoe structure 18 is supported and outwardly biased by means ofgenerally vertically disposed spring strap members, as at 30, eachhaving a vertical inner leg 31 rigidly secured to peripheral roof wall19 by meansof bolts or rivets 32, and a radially outwardly and upwardlyinclined outer leg 33 connected to inner leg 31 by means of a resilientloop 34. Each outer leg 33 (FIG. 8) has a curved, upper extremity 35with an aperture loosely received upon one of the bolts 28 and betweenan inner plate 37 and an outer nut 38 thereon. Accordingly, theattachment of support leg 33 to the upper portion of the shoe structuremay pivot or rock as the shoe structure is distorted radially due toirregularities in the tank shell face.

Pairs of preferably metal straps 40 and 41 are pivotally supported byand depend from thebolts 27 projecting inwardly from reinforcing bars 23and 24. These straps depend along the inner face of shoe structure 18and are secured at their lower extremities to a weighted'crossbar 45which extends through a loop 46 formed at the lower edge of sheetingenvelope 20. Due to the reduced thickness of the upper edge portion 47of the shoe structure and the inward disposition of weight bar 45, thisbar acts eccentrically in the mannerof a pendulum to bias the shoestructure along its entire depth against the inner face of the tankshell.

The form in FIGS. 1a, 3, 4, and 5 embodies a plurality of independentshoe members, as at 50 and 51. Each shoe member comprises a thin metalbacking plate 52 or 53 and a sheet of fluidtight, flexible material 54or 55* with top edges secured to the plates by bolts 56 and bottom edgesfolded upon themselves as at 57 to form a flap 58 inserted betweenbacking plate 52 and padding 66 and secured to the backing plate bybolts 59 and 60. Sheet attaching bolts 56 at the upper edge of thebacking plate also secure thereto the upper edge of a flexible sealcurtain 62 which traverses the clearance between peripheral wall 63 ofthe roof and the upper edge portions of the shoe members-The curtain issecured to an angle bar 64 at the upper comer of the roof by means ofbolts 65. Flexible sheeting 54, together with backing plate 52 of eachshoe struc' ture, forms a fluidtight envelope which is internally packedwith a suitable resilient or cellular material 66, such as expandedpolyurethane foam or the like.

Each shoe member is supported and biased against the inner face of tankshell '67 by means of one or more circumferentially spaced,vertically-disposed leaf or strap springs 68 intermediately secured toroof peripheral wall 63 by boltsor rivets 69. The upper part of eachspring strap member extends radially outwardly and upwardly anddownwardly from the roof and is pivotally or rockingly secured to theupper edge portion of one of the shoe members, in the same manner asshown in FIG. 8, by means of a stud 70 loosely receiving the curvedextremity 71 of the spring member which is secured in position by a nut72. The lower portion of each spring strap member extends radiallyoutwardly and downwardly from the roof and has a curved, lower extremity73 slidably bearing against the lower portion of the shoe member, thespring strap cooperating with the rigid backing plate 52 to bias theresilient outer surface of the shoe member against the tank shell withenvelope sheeting 54 in rubbing contact therewith.

In an exemplary form of standard seal according to this form of theinvention, each shoe member 50, 51 comprises a polyurethane foam pad ofapproximately l /zinches thickness and is approximately 8 feet incircumferential dimension and 2 feet 4 inches in height. Since theseshoes will be used in tanks varying widely in diameter--for instance,from 40 to 250 feetshoes of alternative lengths will be provided for usewith assemblies of standard shoes to complete encirclement of the tank.FIG. 5 illustrates in section a joint between abutting longitudinaledges of a pair of adjacent shoe members 50 and 51. A piece of flexibleenvelope fabric 75 is inserted between polyurethane packing 66 and theinner face of backing plate 52 and is secured thereto by bolts, as at76. The outer edge of piece 75 overlies and is secured by bolts 77a tothe corresponding edge of envelope sheeting 54, and the two pieces ofsheeting are feathered as shown to form an inclined edge 78. Theflexible envelope sheeting 55 of the adjacent shoe member 51 issimilarly secured by bolts, as at 79, to the edge of a sheeting strip 80which is inserted between polyurethane packing 54a and backing plate 53,the feathering of this part being complementary to the feathered partformed between sheeting pieces 54 and 75 of the adjacent shoe member toform an inclined edge 81 which abuts edge 78.

Backing plates 52 and 53 may overlap at their juncture, as at 82, andthe assembly thereof is resiliently maintained by a spring strip 83 ofdouble-U configuration which is secured to the shoe members bypreviously-mentioned bolts 76 and 77. In the assembly, a substantiallyfluidtight joint is provided between the abutting shoe members, yetthese members including the backing plate portions thereof are free towork to accommodate irregularities in the face of the tank shell.

FIGS. 6 and 7 show a modified form of shoe supported and biased byvertically disposed spring 'strap members 85 of generally bow-shapedconfiguration, as in the previous form. Each of the independent shoes,however, is formed of a relatively thin metal plate as 86 or 91 providedalong its upper and lower edges with inwardly inclined lips 87 and 88which enable the shoe to ride over irregularities in the inner face ofthe tank shell 89. FIG. 9 is a detail horizontal cross sectionillustrating a joint between adjacent shoe plates, as 86 and 91, andshowing a spring strap 92 of double-U configuration as in FIG. 5,secured to the shoe plates by bolts 93. The edge of seal curtain 94 issecured to the top edges'of shoe plates 86, 91, etc., by bolts 95 andpressure plates 96. Preferably, at least a pair of the vertical strapsprings 85 may be utilized to support and bias each shoe, but thisnumber will depend upon the circumferential expanse of the shoe, whichmay be similar to that of the shoes in FIGS. 3, 4, and 5.

Various forms and features may be modified as will occur to thoseskilled in the art, and the exclusive use is contemplated of allmodifications as will occur to those skilled in the art and comingwithin the scope of the appended claims.

Iclaim:

1. In a tank having a tank shell and a floating roof therein withclearance space therebetween, seal means in said space comprising aplurality of shoes arranged circumferentially about and with facessealingly and slidably abutting the inner face of said shell, pliablesealing means extending continuously around said space and traversingthe same radially between the upper portions of said shoes and saidroof, additional sealing means nonrigidly connecting the adjacent endsof said shoes, and vertically disposed, generally bow-shaped springstraps with their center portions secured to the periphery of said roofand extending radially outwardly and upwardly and downwardly therefrom,the upper portions of said straps being rockingly secured to said shoesadjacent said upper portions thereof and beneath said pliable sealingmeans and the lower portions of said straps slidably abutting the innerfaces of said shoes for resiliently supporting said shoes and saidsealing means relative to said roof and biasing sa d shoes against theinner face of said tank shell.

2. In a tank shell having a floating roof therein with clearance spacetherebetween, seal means in said space comprising a plurality of shoesarranged circumferentially about and with faces sealingly and slidablyabutting the inner face of said shell, pliable sealing means extendingcontinuously around said space and traversing the same radially betweenthe upper portions of said shoes and said roof, additional sealing meansnonrigidly connecting the adjacent ends of said shoes, and verticallydisposed spring straps secured to the periphery of said roof andextending radially outwardly and upwardly therefrom and pivotallysecured to said shoes adjacent said upper portions thereof and beneathsaid pliable sealing means for resiliently supporting said shoes andsaid sealing means relative to said roof and biasing said shoes againstthe inner face of said tank shell, each of said shoes comprising aform-sustaining backing plate, a sheet of pliable, fluidtight materialsealingly secured at its edges to the outer face of said plate forbearing against the inner face of said tank shell, and a packing ofresilient material between said plate and said sheet for accommodatingirregularities in the shell face, said sheet of material forming anenvelope with said backing plate, at least the lower edge portions ofsaid envelope being sealed to prevent access of tank liquid to thepacking within said envelope, the adjacent side edges of said pliablematerial and said packing being feathered to respectively overlie andunderlie each other and thereby form a fluid-resistant joint betweensaid shoes while permitting independent working of said shoes toaccommodate irregularities in the tank shell face.

3. In a floating roof tank, seal means as described in claim 2 furtherincluding tensionally resilient spring means bridging the joints betweenadjacent shoes for maintaining the alignment thereof. 1

1. In a tank having a tank shell and a floating roof therein withclearance space therebetween, seal means in said space comprising aplurality of shoes arranged circumferentially about and with facessealingly and slidably abutting the inner face of said shell, pliablesealing means extending continuously around said space and traversingthe same radially between the upper portions of said shoes and saidroof, additional sealing means nonrigidly connecting the adjacent endsof said shoes, and vertically disposed, generally bow-shaped springstraps with their center portions secured to the periphery of said roofand extending radially outwardly and upwardly and downwardly therefrom,the upper portions of said straps being rockingly secured to said shoesadjacent said upper portions thereof and beneath said pliable sealingmeans and the lower portions of said straps slidably abutting the innerfaces of said shoes for resiliently supporting said shoes and saidsealing means relative to said roof and biasing said shoes against theinner face of said tank shell.
 2. In a tank shell having a floating rooftherein with clearance space therebetween, seal means in said spacecomprising a plurality of shoes arranged circumferentially about andwith faces sealingly and slidably abutting the inner face of said shell,pliable sealing means extending continuously around said space andtraversing the same radially between the upper portions of said shoesand said roof, additional sealing means nonrigidly connecting theadjacent ends of said shoes, and vertically disposed spring strapssecured to the periphery of said roof and extending radially outwardlyand upwardly therefrom and pivotally secured to said shoes adjacent saidupper portions thereof and beneath said pliable sealing means forresiliently supporting said shoes and said sealing means relative tosaid roof and biasing said shoes against the inner face of said tankshell, each of said shoes comprising a form-sustaining backing plate, asheet of pliable, fluidtight material sealingly secured at its edges tothe outer face of said plate for bearing against the inner face of saidtank shell, and a packing of resilient material between said plate andsaid sheet for accommodating irregularities in the shell face, saidsheet of material forming an envelope with said backing plate, at leastthe lower edge portions of said envelope being sealed to prevent accessof tank liquid to the packing within said envelope, the adjacent sideedges of said pliable material and said packing being feathered torespectively overlie and underlie each other and thereby form afluid-resistant joint between said shoes while permitting independentworking of said shoes to accommodate irregularities in the tank shellface.
 3. In a floating roof tank, seal means as described in claim 2further including tensionally resilient spring means bridging the jointsbetween adjacent shoes for maintaining the alignment thereof.